Fluid fuel burner mechanism



Jan. 19, 1937. M cABE FLUID FUEL BURNER MECHANISM Filed July 15, 1952 4 Sheets-Sheet l INVENTOR [RA E CABE BY ATTORNEY Jan. 19, 1937. MccABE 2,068,425

FLUID FUEL BURNER MECHANISM Filed July 15, 1932 A O i V & i

I S o INVENTOR IRA EM CABE ATTORNEY 4 Sheets-Sheet 2 Jane 19, 193 7.. 2,068,425

I. E. M CABE FLUID FUEL BURNER MECHANISM Filed July 15, 1932 4 Sheets-Sheet 5 6 m zm C l. M a M ATTORNEY Jan. 19, 1937. l. E. M -CABE 2,063,425

FLUID FUEL BURNER MECHANISM Filed July 13, 1932 4 Sheets-Sheet 4 INVENTOR IRA E. M CABE L B o H ARANAQAAK Patented Jan. 19, 1937 TED STATES PATENT OFFICE 8 Claims.

This invention relates to improvements in fluid fuel burner mechanisms'and more particularly to a burner of this type employing a gaseous fuel and including an electrical ignition and control device of this character must include positive.

means for igniting the gas, as well as positive means for cutting off the supply of gas in the event of failure of the device to function properly, as a gaseous fuel not properly controlled is very dangerous and may cause serious damage to the building in which the heating appliance is installed. Many different forms of igniting devices and safety means have'been constructed to protect the user, however, the majority of such devices have certain periods of operation unguarded and it is an object of this invention to provide an electrically operated and controlled device of this character which is automatic in its functions, when it is desired to produce heat in the building, to positively bring the ignition device into operation before the fuel is admitted into the combustion chamber and thereafter to employ the heat of combustion in combination with the ignitiondevice to reduce the amount of electric current necessary to maintain the safety device operative and upon eitherthe cessation of the current or failure of combustion to cut off the supply of gaseous fuel in the combustion chamher and, furthermore, if this is caused by the failure of combustion alone, the control device is so constructed as to render the heating device inoperative until manually restarted, but if this is caused by the cessation of electric current the resumption of the current automatically causes the control device to actuate the igniter to become operative, but delays the admission of fuel until the ignition device is operating sufficiently to positively and instantaneously ignite the fuel when so admitted.

In a device constructed in accordance with this invention, the control renders the system inoperative if abnormal causes result in the destruction of the operating parts of the control or ignition element employed.

This invention contemplates the use of an electrical resistance igniter which becomes incandescent upon the passage of an electric current therethrough and contemplates the employment for this purpose of a commercial electrical resistance material which possesses the property of being quickly brought to incandescence upon the passage of the electric current therethrough when cold and thereafter withstanding excessive high temperatures without deterioration, making it especially advantageous for this purpose, and also possessing the additional property as its temperature rises of offering decreasing resistance to almost an unlimited degree. Such commercial resistance material has heretofore been employed by this applicant as disclosed in his prior copending application, Serial No. 544,516, filed June 15, 1931 and is known to the trade as Dmhy a product of the Globar Corporation of Niagara Falls, New York, and is made in accordance with United States Patent No. l,8i2,088, dated January 19, 1932 which is the property of said corporation. This invention further contemplates the employment in the control of a number of com-- mercial mercury tube switches connected with mechanism for controlling the operation. of the gas burner system. and a relay for actuating said switches to open and close the various circuits,

preferably of the type disclosed in the applicants co-pending application Serial No. 500,747, filed December 8, 1930, which provides for a movable coil transformer which when energized results in the repulsion of the movable coil to perform physical work.

With these and other objects in view, reference is made to the accompanying sheets of drawings which illustrate a preferred form of this invention with the understanding that minor detail changes may be made therein and its adaptation to other uses may be made without departing from the scope thereof.

In the drawings- Figure 1 illustrates a practical application of this invention showing a gaseous fuel burner for domestic purposes, partly in section, with a schematic wiring diagram of the control apparatus attached thereto, in which the parts of the control are in the position assumed when the burner is operating to produce heat. I

Figure 2 is a schematic wiring diagram illustrating the position of the parts of the control assumed when the burner mechanism is idle or cold.

Figure 3 is an enlarged detail view in end elevation of the control panel with parts thereof the burner is idle or cold, similar to the position shown in Figure 2.

Figure 5 is a detached detail view, similar to Figure, 4, illustrating the position assumed by the operating parts of the control upon a flame failure. i

Figure 6 is a schematic wiring diagram illustrating the operation of the switches of the control upon flame failure, as illustrated in Figure 5.

Figure 7 is a detached detail view of the operating parts of the control mechanism assumed in the normal running position, as illustrated in the schematic wiring diagram shown in Figure 1.

Figure 8 is an enlarged detail view in front elevation of the preferred form of ignition device.

Figure 9 is a view in end elevation of Figure 8.

A practical embodiment of this invention is illustrated in Figure 1 in which a commercial gaseous fuel heater I is shown with a gas burner 2 in position and connected by a gas feed pipe 3 to a source of gaseous fuel supply, not shown. An electrical ignition device 4 is shown supported above the burner 2 and in the path of the flame therefrom, which ignition device is illustrated in detail in Figures 8 and 9. The panel 5 supports the control mechanism which is shown in connection with the schematic wiring diagram. In this diagram, the wire L is connected to the commercial source of electricity and leads the current therefrom through the boiler control B, of commercial construction, and through the room thermostat T, also of commercial construction,

to the hand switch H and thence through a pressure control switch P, of commercial form such as disclosed in Patent No. 1,841,326, January 12, 1932 in the gas feed pipe 3 to a binding post 6 upon the control panel 5. The wire L connects the binding post 1 upon the control panel with the other line leading to the commercial supply of electricity. 1

The control panel 5 mounts a repulsion relay of the type disclosed in the applicants co-pending application, Serial No. 508,185 filed January 12, 1931, for use in alternating current electric lines and includes a rectangular core 8 having a stationary secondary coil 9 about one side of the lower end of the core with a primary coil Ill wound about and movably mounted upon the same leg of the core 8 and adapted to reciprocate above the coil 9. The primary coil [0 is carried by a bracket Ii preferably pivotally mounted at Ila upon the other side of the core 8 which bracket is extended to mount a valve switch V and a shunt switch S, which switches as heretofore stated are preferably of the mercury tube type, so that reciprocation of the coil III will impart a. tilting movement to the said switches to cause them to be closed upon appreaching one end of travel of the coil and open upon approaching the other end of travel. A safety switch Y, of the same mercury tube type, is carried by a counterweighted bracket l2 provided with a counterweight Ila preferably pivoted at the same point I la as the bracket It). An electromagnet M is carried on that portion of the bracket ll extending on the other side of its pivotal point Ila from the coil III, and supports a pivoted armature l3 mounted between ears l3a extending from the center clamp plates of the magnet core.

The mercury tube switches S and Y are adjustably mounted upon the members that support and carry themand are so arranged that when the burner is in the idle position, the primary coil ID will rest upon the secondary coil 5 causing the valve switch V to assume the open position and the shunt switch S assume the closed position and the counterweighted safety switch Y assume the closed position, as shown in the schematic diagram, Figure 2, and in the detailed view, Figure 5. One terminal of the safety switch Y is connected to the binding post 5 and the other terminal is connected to one terminal of the shunt switch S. The other terminal of the shunt switch S is connected to the binding post M, which binding post is connected to one end of the windings of the primary coil ID, the other end of which is connected to the binding post 1. An electrically operated gas valve G is connected to control the passage of fuel through the gas feed pipe 3. One terminal of the valve switch V is connected to the binding post 6. The other terminal of the valve switch V is connected to the operating mechanism of the gas valve G which is also provided with an electrical connection to the binding post 15 which binding post in turn is connected to the binding post 1. One end of the windings of the secondary coil 5 is connected through binding post 16 to one side of the electrical resistance igniter 4, the other side of which is connected through binding post I"! to the other end of the winding of the coil 9.

When the hand switch H is closed and the room thermostat is opened and closed by the temperature of the building a call for heat causes the closing of the thermostat and the electric current passes along the line L through the boiler control 13, room thermostat T, and switch H and control switch P to the binding post 6. The valve switch V being in the open position and the safety switch Y being in the closed position, the current then passes through the closed shunt switch S and about the windings of the primary coil ID to binding post 1 and then travels back through L to the source of electricity. This passage of the current through the windings of the primary coil I0 induces a current in the secondary coil 9 which is in circuit with the electrical resistance igniter 4, heretofore described as offering high resistance when cold. As the current continues to pass through the igniter 4, its temperature increases and, as heretofore described, its conductivity also increases until suflicient current is allowed to flow therethrough to cause an electrical repulsion to occur between the coils 9 and I0. Coil 9 being stationary will repel coil 10 causing the bracket il to rotate about its pivotal point and thereby cause the valve switch V to close. whereupon the incoming current at binding post 6 will divide, part passing through the valve switch V to open the gas valve G. The greater the temperature of the ignition device 4 the higher the movable coil rises. The switches V and S upon the bracket H are so adjusted that apredetermined time after the ignition element 4 has reached a term perature required for igniting the gas, the movable coil will have risen far enough to first tilt the valve switch V to closed position and thereafter the shunt switch S to open position as the coil approaches the upper limit of its travel. The shunt switch in opening its circuit allows for the energization of the magnet M so that the portion of the current heretofore passing through the safety switch Y and shunt switch S thereafter passes through the magnet M to the binding post H. The pivoted armature I3 of the magnet is provided with a catch I8 adapted, when the primary 0011' has been repelled sufficiently to tilt the shunt switch S to open position and cause the magnet M to attract its armature l3, to engage a toothed segment l9 upon the counterweighted safety switch carrying pivoted bracket I2. The function of the magnet M when first energized is to introduce resistance in the circuit to the primary coil H] to reduce to the minimum, during the period of combustion, the amount of current used in maintaining the system in operation. To prevent the desired reduction in current consumption from allowing the movable coil I to fall suificiently to open the gas valve circuit through the valve switch V the weight of the counterweighted safety switch supporting bracket l2, having been engaged by the catch of the armature I3, is picked up by the energization of the magnet M'andad'ded to that side of the bracket H, to aid in counterbalancing the coil ill, so that the switch V is maintained closed to allow continuous operation of the burner. The temperature of the ignition device is maintained jointly by the heat from the burning gas and by the reduced amount of current passing through it at a temperature when the element offers but little electrical resistance so that the current, which is permitted to pass, with the aid of the counterbalancing parts, maintain the coil Ill in its repelled position. Without the passage of some current the counterbalancing parts alone would not accomplish this result.

When the thermostat T opens, caused by the surrounding temperature having reached the desired degree, the circuit to the commercial source is opened through the magnet M, deenergizing the armature l3 and allowing the counterweight thereon to withdraw the catch l8 from engagement with the counterweighted bracket l2, whereupon the coil l0 freed of this weight, falls to rest above the stationary coil and in so doing causes the bracket l l to tilt the valve switch V to open position and thereby cause the gas valve G to close and cut off the supply of fuel and at the same time cause the closing of the shunt switch S.

The above is a description of the normal function of the control when actuated by the room thermostat to start and stop the burner mechanism. In the event the room thermostat calls for heat when the burning mechanism is idle or cold and the igniter 4 is brought to ignition temperature, but for some reason or other fuel is not supplied to the burner. 2, the movable coil ID as before described, rises as the temperature of the igniter increases to raise its conductivity. The shunt switch S is opened and the valve switch V is closed and the magnet M energized to place resistance in the circuit of the movable primary coil l0 and cause the armature l3 to engage the bracket Ill. The absence of the heat from the burning gas causes the igniting element 4 to cool since the current flow therethrough has been reduced by the introduction of the resistance of the magnet M 'in the circuit with the primary coil Ill. As the igniting element 4 cools to such a degree as to offer resistance to the passage of the current therethrough, which current is induced in the stationary secondary coil 9, the electrical repulson force also reduces, whereby the floating secondary coil l0 descends. The weight of the counterbalancing parts are so arranged as not to be sufficient to completely balance the coil It, so that as the coil descends. the magnet M connected by its armature l3 to the counterweighted bracket I2, is lifted. This movement imparts rotation of the bracket l2 to open the safety switch Y before closing the shunt switch S. When this occurs, as the coil descends sufiiciently to open the valve switch V and close the shunt switch S, the circuit through the shunt switch cannot be completed as the safety switch Y is open and, .therefore, the magnet M remains energized and the burner system is rendered inoperative. When corrective measures have been made to eliminate the cause which prevented the supply of fuel, the control can be placed in normal-operative position by interrupting the circuit from the source of electricity, as by manually operating the room thermostat or by manually opening and closing the hand switch H, the opening of which circuit deenergizes the magnet which allows all of the parts of the control upon the panel to return to their normal starting positions.

The control would function in a similar manner should at any time during its operation, the flame become extinguished because" the lack of combustion of the fuel would result in the cooling of the ignition element and cause the control to act as above described.

In the event of interruption of the current from the commercial source of supply and such interruption occurs prior to combustion being initiated no harm can be done, as the normal I operation of the control has not proceeded sufficiently to open the gas valve G and the control will immediately return to its starting position and be adapted to resume operation upon resumption of the current or, if the interruption be but momentary, to continue in its normal cycle of operation. Should the current interruption occur during combustion and be only momentary, the magnet M will be deenergized freeing the catch l8 from the counterweighted bracket 12, but the igniter 4 being hot and the resistance shunted from the circuit, the coil l0 immediately rises to cause the magnet M to be again energized engaging the catch IS with the bracket l2 and the control proceeds to function with but a momentary closing of the gas valve. In the event that the interruption be of greater duration, the control would operate in the same manner as if the room thermostat had opened the circuit and the parts of the control would return to the normal cold or idle position, so that upon the resumption of current, presuming the room thermostat be closed, the control would re-cycle and function in the same manner as if the room thermostat had called for heat.

The character of the ignition device forms an essential element of this invention inasmuch as the peculiar properties of the material used are employed as part of the control mechanism.

As heretofore stated, the ignition element 4 is an electrical resistance element of a commercial material known as Durhy and possesses certain characteristics which are employed in carrying out this invention. The element 4 is shown in Figures 8 and 9 as being a short length of this material, preferably of cylindrical form and provided with caps 20 mounted upon each end forming electrical connections with supports 2| of material able to withstand high temperatures, such as chrome nickle or chrome silicon alloys or steels, in the form of wires, which, in turn, are mounted upon a,block 2?. of insulating material provided with binding posts 23 for each support, respectively, which binding posts each support a spring clip 24 held in electric connection therein. Each clip 24 is adapted to engage an enlarged connector 25 supported on a bracket 26 and provided with binding posts 21 adapted to be connected in circuit with the binding posts l6 and ll of the panel and which bracket 26 is shown in Figure 1 as being suitably mounted to position the ignition element 4 in the path of the gaseous fuel issuing from the burner 2 and when ignited to be subjected to the heat of combustion. This particular element 4 possesses the characteristics of being an electric conductor which offers considerable reslstanceto the passage of current when cold, but also possesses the characteristic of lessening the resistance as its temperature increases either by the passage of the electric current therethrough or by application of external heat.

As above described this igniter is placed in the secondary circuit of the relay which is energized when the room thermostat calls for heat causing the current from the secondary coil 9 to pass through the resistance element, slowly at first when the element is cold, and as the temperature of the element increases by the passage of the current the intensity of the current will be correspondingly increased until the element is brought to incandescence and the induced cur rent of sufficient magnitude to repel the coil Hi to open the shunt switch S. The bringing of the element 4 to incandescence occurs while the valve switch V remains open and the valve switch V is closed shortly before the shunt switch is opened,

which will allow the gaseous fuel to become ignited. The additional heat upon the element oc casioned by the combustion of the fuel taken together with its increased conductivity is c0mpensated for by the provision of the magnet M whichiis placed in circuit with the primary coil when the shunt switch S is opened and this resistance so introduced is of such character as to reduce the flow of current to a point whereupon cessation of combustion the cooling of the element increases its resistance until the current flow is so reduced as to allow the weight of the coil l0 to overcome that of the counterbalanci'ng parts and descend and thereby open the safety switch Y, as shown in the schematic wiring diagram in Figure 6, so that upon failure of combustion the circuit through the magnet M remains closed, while the circuits through the valve switch V and the safety switch Y remain open, necessitating a manual reset before the burner can again operate normally.

If for any reason the ignition element 4 becomes damaged to such anextent that the circuit is broken while the burner is idle, no current can be induced in the secondary coil'9 and the control parts will remain in their idle position as shown in the schematic diagram in Figure 2. If the circult is broken through the ignition element 4 while the device is in normal running position as shown in the schematic diagram of Figure 1, as no current is induced in the secondary coil 9, the coil III will descend, as shown in the schematic wiring diagram 2, which will open the valve switch V and close the shunt switch S thereby deenergizing the magnet M and the device cannot operate again until the defective ignition element is re placed,

From the above it is seen that it is impossible to open the fuel supply valve until the ignition element is operating sufliciently to ignite the fuel so supplied to the combustion chamber. Should the gas supply be cut off, while the burner is in operation at some point between the gas valve and source of supply, the flame becomes extinguished from lack of fuel and the valve switch V is so adjusted that it will close the fuel valve before the ignition element cools below the igniting point of the fuel, so that if, the fuel is re plenished before the ignition element cools to cause the closing of the gas valve, the element will still be of sufficient temperature to ignite it.

The above reduces the hazards generally found in other controls which fail to provide upon flame failure, following a momentary fuel interruption, means to ignite the replenished fuel supply ontering the burner. In other words, controls as a rule heretofore have broken the ignition circuit after combustion and in the event of flame failure the fuel valve is left open and ignition is not provided until the device returns to its start ing point, from which it is evident that fuel sup plied to a hot fire box or combustion chamber, following a momentary fuel interruption, would result in an explosion unless means, as provided by this invention, be available to ignite the replenished fuel as it enters the combustion chamber.

The detachable clip connection of the igniter block 22 to the normally fixed bracket 26 readily allows the removal of the igniter, should it be come damaged or desirable to remove it for any other reason, by simply exerting enough pull upon the block to remove the clips 24 from the fixed connection 25 and the igniter is readily replaced by reversing the action, in other words,

the igniter may be removed or replaced without the usual loosening and tightening of binding post connectors.

What I claim is:

1. An automatic electrically controlled fluid fuel burning mechanism including a burner connected to a source of fuel, an igniter in the path of the fuel from the burner subjected to the heat of the ignited fuel, said igniter including an electrical resistance element adapted to he brought to incandescence upon the passage of an electric current therethrough increasing in conductivity as its temperature increases, means for establishing an electric circuit through said igniter element, including a constant current transformer having its floating primary coil in circuit with a source of electricity and its secondary coil in circuit with said igniter element, means normally closing the flow of fuel to the burner, and means actuated by the floating of the said coil to operate said means to admit fuel to the burner.

2'. An automatic electrically controlled fluid fuel burning mechanism including a burner connected to a source of fuel, an igniter in the path of. the fuel from the burner subjected to the heat of the ignited fuel, said lgniter including an electrical resistance element adapted to be brought to incandescence upon the passage of an electric current therethrough increasing in com ductivity as its temperature increases, means for establishing an electric circuit through said ig niter element, including a constant current transformer having its floating primary coil in circuit with a source of electricity and its secondary coil in circuit with said igniter element, means normally closing the flow of fuel to the burner, means actuated by the floating of the said coil to operate said means to admit fuel to the burner upon a predetermined movement of said primary coil allowing the igniter element to become incandescent prior to the flow of fuel, and means rendered operative after a further predetermined floating movement of. the primary coil to reduce the flow of current therethrough.

3. The structure of claim 2 W1 ,rein said last named means includes the of an electromagnet and in which a pivoted armature and a pivoted counterweight are provided with means actuated by the energization of the magnet to connect the counterweight to the primary coil to hold the primary coil in the predetermined position to maintain the fuel flow open.

4. The structure of claim 2 wherein an electrically operated valve controls the flow of fuel and in which is included a normally open switch adapted to be closed by the floating of the primary coil to a predetermined position and means to establish a circuit through the closed valve switch to actuate the valve to open.

5. The structure of claim 3 wherein said last named means includes the winding of an electromagnet and in which a pivoted armature and a pivoted counterweight are provided with means actuated by the energization of the magnet to connect the counterweight to the primary coil to hold the primary coil in the predetermined position to maintain the fuel flow open wherein an electrically operated valve controls the flow of fuel and in which is included a normally open switch adapted to he closed by the floating oi". the primary coil to a predetermined position and means to establish a circuit through theclosed valve switch to actuate the valye to open.

ii. An automatically electrically operated and controlled fluid fuel burning mechanism includ ing a source of electricity, a variable resistance igniter increasing in conductivity upon increas= ing temperature in the path of the burning fuel, a constant current transformer relay having a floating primary coil and a stationary secondary coil, said igniter losing in circuit with said sec-= ondary coil, an electrically operated tuel valve, a normally open valve switch, an electrical limiting resistance, a normally closed shunt switch, means to establish a circuit irom the source through the closed shunt switch and primary coil of said relay, means to close the valve switch and open the shunt switch actuated by said relay as the conductivity of the igniter increases to per= init suficient current to flow through the secondary coil to repel the primary'coil a predetermined distance, means to establish a circuit through the closed valve switch to open the valve, means to establish a circuit from the source through the limiting resistance and primary of the relay upon the opening of the shunt switch.

7. The structure of c1aim'6 including a pivoted arm attached to the floatingprimary coil at one end and supporting the limiting resistance at the other, a pivotally mounted safety switch interposed between the source and the relay and other switches having a counterweight to normally hold the safety switch closed to complete said circuits as they may be established, and means actuated by establishing the circuit through said resistance to engage the safety switch to said arm to open the safety switch upon a predetermined descending movement of the primary coil of the relay.

8. tin electrical ignition and safety device for controlling the operation of a fluid fuel burner, including a source of electricity, a variable resistance igniter decreasing in resistance upon increasing temperature in the path of the burner flame, means connecting said igniter in circuit with said source, a. switch in circuit with said source, means controlling the feeding of fuel to said burner actuated by the closing. of said switch, a limiting resistance in circuit with said source, a circuit and a second switch in said circuit shunting said resistance, an electrically operated switch actuating means in circuit with said source including said means for connecting the igniter in said circuit and responding to the conjoint closing of the circuit therethrough and conductivity oi said. igniter upon attaining ignition temperature to actuate the first switch to feed fuel and, thereafter, upon the conductivity of said igniter becoming greater than required for lg nition temperature, to actuate said second switch to introduce the limiting resistance, and thereafter the combined heat of the burner flame and energized igniter maintains the temperature of the igniter sufilcient to render its conductivity commensurate with the requirements of said means to continue to feed fuel and sufficient for ignition purposes.

RA E. McCABE. 

